In a broad sense, a power supply includes a power source and a power circuit. Common power circuits include various regulated power supplies, uninterrupted power supplies, and the like. These power circuits need to process a voltage provided by a power source, to obtain a voltage that is required by an electrical appliance (that is, a load). The processed voltage is stable. Therefore, the power circuit in the power supply is a very important part. To operate normally, the electrical appliance (that is, a load) needs a desirable power circuit.
Due to an actual application requirement, a voltage power supply requirement for a load extends to more voltage domains from two cases including a single operating voltage and a voltage that is lower than a threshold. That is, a common chip power supply technology relates to supply of power for a normal operating voltage of the load or for a voltage lower than a threshold. However, as a semiconductor process advances, performance of a chip under different supply voltages may switch between different states, so as to meet requirements in different application scenarios and different operating modes. In addition, because the load is affected by various factors such as process variation, a temperature impact, and a power fluctuation, a supply voltage of the load needs to change in real time.
However, in the prior art, an on-chip power supply has some disadvantages in design. For example, a specified module needs to be aimed from the beginning of the design, that is, a status of a load current needs to be evaluated in advance and a specific value range of an adjustable resistor needs to be provided. However, if the load current is inaccurately estimated or the load varies greatly in different scenarios, an output voltage range is risky. As shown in FIG. 1, FIG. 1 is a schematic diagram of a basic principle of a linear on-chip power supply in the prior art according to an embodiment in the present disclosure. In the linear on-chip power supply, stability of an output voltage Vout is maintained by adjusting an R1do resistor. In a circuit corresponding to FIG. 1, it can be learned that a proportional relationship needs to be maintained between the R1do and an Rload to obtain an expected output voltage Vout. Therefore, in this implementation solution, practicability and flexibility of the power supply cannot be met.